Sine and angle calculator



Nov. 4 1924. 1,514,323

' J. J. KIRCHNER SINE AND ANGLE CALCULATOR Filed March 13, 1922 2.5 llllllLlllLlllll'ln Kinsmen.

Patented Nov. 4, 1924.

JOHN J. KIROHNER, OF BALTIMORE, MIABYLAND.

TEN- FFICE.

SINE AND ANGLE CALCULATOR.

To all whom it may concern:

Be it known that 1, JOHN J. KIRC'HNER, a citizen of the United States, residing at Baltimore, Maryland, have invented a new and useful Tool Known as a Sine and Angle Calculator, of which the following is a specification.

This invention relates to a combined tool or implement especially designed for the use of mechanics in the building and other trades, having a number of uses of particular merit some of which are set forth be low.

One of the objects of this invention is to supply such a tool or implement which is simple and durable, is of great utility, and yet is compact, being conveniently folded up when not in use.

Other objects and advantages will be obvious from the more detailed description set forth below.

In the drawings, Figure 1 represents the tool assembled and ready for use; Figure 2 shows a top view of member C; Figures and 3 show top and side views of member B; Figure A shows a side view of member A; Figures 5 and 5 show a detail of the pivot joint used to secure the members A and C in position; while Figure 6 is a detail in section of member C taken on line a2--m.

As illustrated in the drawings, the tool is preferably composed of three members lettered A, B, and C pivoted together at and 21,-the members A and B, hereinafter called arms or blades, being capable of movements of ninety degrees each about their respective pivot points. Member A is capable of an additional longitudinal movement in the slot 22 in member C. The member A has a beveled edge 23 graduated in one thirty-seconds of an inch. Member B has its inner edge 24 likewise graduated in thirty-seconds of an inch, while its pivoted end 25 carries calibrations in degreesfrom O to 90 as illustrated.

On the top edge of B there is a mark 26 registering a zero point as shown in Figure 3, the function of which is set forth below.

Member B also carries another scale 27 on its front face as illustrated for deter- 3 sides, .57735 8 sides, 1.30656 Radius of ciroumscribing circle: 4 .70711 9 1.46100 Length of side multiplied 5 .85065 10 161803 by the following: 0 1.00000 11 1.77473 MemberC has its upper edge 28 graduated in thirtyseconds of an inch. Its right hand edge is finished with a semi-circular head 29. This semi-circular head may be made an integral part of the member C, but it is preferred to have it a separate piece of metal which is then rigidly attached to the member C. This semi-circular portion is calibrated as illustrated at 30, the calibrations being carried over the edge of this portion, thus being adapted to coast with the zero point 26 on the top edge of member B described above. The inner edge of member B forming this semicircular edge is beveled as at 31 in order to contact ';with the degree graduations on blade B.

Against the lower edge of member 0 there is rigidly attached a piece of metal 32 whose function is to serve as a head piece when the tool is used as a bevel and trisquare.

The pivot 33 used to attach members A and C is shown in Figures 5 and 5 and consists of a circular member 34 provided with a lug 35 adapted tomove in'the groove 22in member G. This pivot also carries a pin 36 to limit the movement of member A. This pin works'in the portion of the quadrant 37 of member A which is cut away as shown in Figure 4.

The pivot used to attach members B and C consists of an ordinary headed screw with a coacting nut. Movement of member B beyond ninety degrees is preferably prevented by means of the lug 38 integral with the. base C.

The following uses are illustrative of the invention, but it is to be understood that this tool has other uses obvious to those skilled in the arts to which it appertains.

For example, in determining standard roof pitches, member A is moved over until its calibrated, beveled edge extended at right angles to member C touches the three inch mark on member C. Member B is then moved on its pivot until the mark representing the desired roof pitch engages the beveled edge of member A. By reading the intersected beveled edge of A the rise in inches in a three inch run is obtained. As a working example, in finding the rise for a roof pitch of one-third, move blade B down until the one-third mark on its top face touches the beveled edge of A. The rise is then read ofi" as two inches, which being in a run of three inches represents eight inches to the foot run. .At the same time the an'glecan be read off in degreeson member B.

Further, the sines and cosines of :any given angles can be readily determined with reference to a given hypotenuse. For example, for an agle of thirty degrees and a hypotenuse of three inches, set B at an angle of thirty degrees. Move blade A at zright angles to member C until It touches thethree inch marlron blade B. The distance measured oil on A is then the" sins of thirty degrees, whilethe reading on base C is 'the cosine, referred to the given distance of three inches.

Again the tool-is easily used as a bevel or a combination bevel and tri-square. As a bevel either blade A or blade B may be used, blade B having the advantage of recording the number of degrees in the angle measu-red. Similarly when used as a bevel and trisqua-re,t he same result may be accomplished, but either blade A or blade B may be used as thebevel or trisquare. For such use the metal rest "32 attached to the base C is placed against the ec'l-ge of the working piece.

Furthermore, the tool has great utility in the making of miter cuts of polygons from three to twelve sides. For example the Zero point 26on the "upper edge of B is set on any desired calibration on the semi-circular head, let us say on numeral three. The blade B then gives the proper angle for the miter out, which angle may also be reado'tf in degrees on 33.

The table referred to above as placed on the reverse side of blade B has several valuable uses. For example, in order to find the radius of the circle necessary to circumscrihe a given regular polygon, the length of the side of the polygon is measured and then multiplied by the appropriate value given in thekta'ble. Assume, by way of illustration, a heptagon with sides 1.7355 inches in length. The number opposite 7 in "the table is 1.15238. Multiplying 1.7355 by 1.15238 we get 2.005 inches as the required radius.

Analogously, to divide a given circle into a given number of parts, and to find the length of the chord subtended by each part, the radius or" the circle .i-sidivided by the value in the :table standing .opposite the number of parts into which the circle is to be divided. The resulting quotient is the length of the required chord. Assuming for example, a circle'of two inch radius to be divided into seven parts. 2 divided by the number opposite 7 in the table, 1.15238 gives 1.7355 as the length of the chord.

While this invention has been fully described and various uses thereotzgiven, -it is understood that the same is described by Way of example only and :notby way o f limitation.

I therefore claim aasimy invention:

1. A calculator comprising a :base memher in combination with oppositel-y pivoted arms, said base member "being provided with longitudinal groove, the upper edge of the base member bein'g:graduated, ahead piece rigidly secured to "the lower edge of the base member, a semi-circular head position at one end (if the :base *mem'ber having calibrations along the outer edge thereof, and having a beveled inner -edge, one arm being pivoted at the sem'i circular head and carrying a zero point on its :upper edge adapted to ieoact with the calibrations on the semi-circular head, the other arm being pivoted in the base for longitudinal movement therein, a "lug on'said latter arm adapted to move in the aforesaid-groove, said lug carrying a pin to limit the move ment of the arm pivoted thereby, :this arm having its inner edge beveled and graduated and adapted tocooperate with the base and the opposite arm to give desired angles and calibrations.

2. A "calculator comprising a base member provided with a longitudinal groove, the upper edge of the base member being graduated, a semi-circular :head positioned at one end :OfTl'lllB base member having "calibrat'ions along the outer edge thereof, an arm pivoted at the semi-circular head and carrying a zerc point on its upper edge adapted "to coact with the calibrations on the semi-'circular head, a :second aarm pivoted to the base member at the-opposite end thereof, adapted to move in the groove aforesaid, this-arm :having its inner edge graduated and adapted to-cooperate with the base and the opposite arm to give -d-esi-red angles and calibrations.

JQHN .J. KIRCHNER. 

